To maximize master tempering valve selection, engineers need to understand minimum flow.
In the world of a plumbing systems design engineer, few tasks are as critical as properly selecting the thermostatic valve(s) that will temper water throughout a new facility. An engineer must consider many important factors when choosing large tempering valves or systems, commonly known as master mixers or Hi/Los.
At a bare minimum, all master tempering valves must be seal board- approved to ASSE 1017. Without this guarantee of performance, bather safety is put at risk. Beyond seal board approval, an engineer then considers maximum flow (at a given pressure drop), to assure a facility's tempered water requirements are met, and next minimum flow, to insure safe bathing during low demand periods (as few as one or two fixtures).